Format Minute to Hours in VB.NET

Here is a sample VB.NET code which can be used to format a number of minutes into hours in two digits and minutes in two digits also.
In short the resultant format is in hours:minutes structure.
For example a time span of 1439 minutes will be formatted to "23:59" and 120 minutes is going to be formatted like "02:00".
A period of 5 minutes is going to be converted to a string value of "00:05". A full day period 1440 minutes is converted by the formatting function to a value "00:00"
Below is the Visual Basic .NET code for the function and the sample ASP.NET web page which has two textboxes and a button on it.
When an integer value is entered into textbox1 and then the button is pressed the formatted or the converted string value is displayed on the textbox2.